Is the race strategy refuel broken ?

I started to do a lot of online racing lately. I started to setup some custom strategies. For some reasons, I can't set the amount of fuel I need for each strategy; the "add fuel" option is disabled, and the fuel time (in seconds) doesn't show up either.

Anyone else having this issue? Anyone able to setup fuel as part as a strategy?

 

In the Race Settings, is the "Pit-stop refuelling allowed?" option set to No? If so, set it to Yes.

 

Thanks, that was the issue. I also was expecting a choice like (enough fuel to the end of race) so we have an auto-computed value vs a hard coded value of liters that almost means nothing since it varies between cars.